Hard disk drives are common information storage devices. FIG. 1a provides an illustration of a typical disk drive unit 100 essentially consisting of a series of rotatable disks 101 mounted on a spindle motor 102, and a Head Stack Assembly (HSA) 130 which is rotatable about an actuator arm axis 111 for accessing data tracks on disks during seeking. The HSA 130 includes at least one drive arm 104 and HGA 150. Typically, a spindling voice-coil motor (VCM) is provided for controlling the motion of the drive arm 104.
Referring to FIG. 1b, the HGA 150 includes a slider 103 having a reading/writing transducer (not shown) imbedded therein, a suspension 190 to load or suspend the slider 103 thereon. When the disk drive is on, a spindle motor 102 will rotate the disk 101 at a high speed, and the slider 103 will fly above the disk 101 due to the air pressure drawn by the rotated disk 101. The slider 103 moves across the surface of the disk 101 in the radius direction under the control of the VCM. With a different track, the slider 103 can read data from or write data to the disk 101. The suspension 190 includes a load beam 106, a base plate 108, a hinge 107 and a flexure 105, all of which are assembled together.
The load beam 106 is connected to the base plate 108 by the hinge 107. A locating hole 112 is formed on the load beam 106 for aligning the load beam 106 with the flexure 105. And the load beam 106 is welded with the flexure for increasing the strength of the entire structure. The base plate 108 is used to enhance structure stiffness of the whole HGA 100.
The flexure 105 is made of flexible material and runs from the hinge 107 to the load beam 106. As shown in FIG. 1c and FIG. 1d, the flexure 105 has a first surface 105a adapted for supporting the slider 103, and a second surface 105b adapted for supporting the extra components 19, 18 with special functions. Concretely, the flexure 105 is a laminated structure including a stainless steel layer 121, two polyimide layers 122, 123 sandwiching the stainless steel layer 121, two copper layers 124, 125 attaching on the polyimide layers 122, 123 respectively, and two cover layers 126, 127 covering on the two copper layers 124, 125 respectively. Namely, the stack layers are symmetrical to the stainless steel layer 121. Basing on this laminated structure, the slider 103 and the extra component 19, 18 can be bonded on the copper layers 124, 125 via solder balls 17, 15 respectively, which are called double sides bonding. Specially, as the stack layers attached on the stainless steel layer 121 on the second surface 105b, the extra component 19, 18 formed thereon can achieve the extra demand of the disk drive unit manufacturers.
However, on the other hand, as the flexure 105 having the laminated structure with seven layers 121-127 are thick and complicated, which increases the manufacturing cost. Thus, this suspension with such a flexure 105 is undesirable to the manufacturer.
Accordingly, it is desired to provide an improved suspension, HGA and disk drive unit to overcome the above-mentioned drawbacks.